The present invention relates to a data reading module, and particularly relates to a data reading module for reading an optical disc.
Data written to an optical disc of fragment recording type (for example, a DVD) can be randomly written; therefore the data regions on the optical disc of fragment recording type are not continuous. The empty regions and the data regions are interlaced. Normally, a recorded map indicating the address of the data regions and empty regions is stored on the optical disc (for HD DVD, it is a bit-map; for Blu-ray disc, it is a space bitmap), and the data reading module (for example, an optical disc driver) reads the optical disc according to the recorded map.
FIG. 1 is a flow chart illustrating the steps of a related art data reading method. As shown in FIG. 1, the method obtains blank blocks with address X and continuous blank blocks Y, and stops the reading head (such as an optical pickup head) at X. Then, Y blank blocks are prepared and the optical pickup head is moved to X+Y for re-starting data reading. Such operation is normally named a “Seek operation”.
However, such an operation needs to stop the reading head each time when an empty region is encountered and then re-start reading again. The performance of the data reading module will gradually degrade.